The influence of a water film on the coefficient of longitudinal friction for a locked wheel was investigated for several conditions of road surface. A skiddometer (type BV 8) was used with the ASTM test tire, and the water film depth was measured by means of a comb with an accuracy of 0.2 mm. The results of the measurements are discussed, and it was concluded that skid resistance reduces when thickness of the water film or speed increases, and that the texture of the surfacing has a great importance for the friction coefficient. A minimum 0.4 mm sand patch depth is proposed (in Sweden) for all road surfacings with tolerable speed above 80 km/h. Macrotexture alone is not sufficient and a certain degree of microtexture is also necessary. Water accumulations thicker than 1 mm due to uneveness, long flowpath, and lack of slope are dangerous and must be avoided. It is also noted that porous asphalt may be considered as a surfacing with a high degree of macrotexture. An additional advantage is that evacuation of water through the layer is possible.

Media Info

  • Features: Figures; References;
  • Pagination: p. 9-15

Subject/Index Terms

Filing Info

  • Accession Number: 00163664
  • Record Type: Publication
  • Report/Paper Numbers: S.C.W. Record 2 Proceeding
  • Files: TRIS
  • Created Date: Mar 14 1978 12:00AM